| It is an effective way to solve the adverse effects produced by drought in breeding drought resistance varieties and improving the drought resistance. 10 hydrids were confected by 7 varieties which widely used in the past or at present based on NC? genetic mating design. The materials were planted by pot experiment, adopting artificial simulation drought method to control the regulate soil moisture at 4 stages:seeding stage; huan seeding stage; root extending stage and vigorous stage. Sceened the drought resistance index, built the drought identification system, evaluated the materials, drought resistance and analysised the genetic characteristics of the drought-resistance traits by measuring the morphological and physiological and biochemical indexes. The main results were as follows:They are differences of the performance between different varieties for the drought, but it the same of several typical varieties at different stage. The results showed that, TN90 was a drought sensitive variety in the early stage(breeding stage and Huan-breeding stage), it was a drought sensitive variety in the late(root extending stage and vigorous stage) the same; K326 and NO.3 of Nan-Jiang are middle or high drought resistance varieties in the early and in the late. It may show that it can be in the early stage of screening drought resistance tobacco variety.Different stages have different drought sensitive indexes. It need to adopt the corresponding indicators of screening drought resistance tobacco variety at different periods. In seeding stage,the indexes of moisture sensitive include: chlorophyll contents and survival rates of the plants. Expressed as that, compared to drought sensitive varieties, the chlorophyll contents of the high drought-resistance varieties is higher and more stable, the seeding survival rates is more than 80%. In huan-seeding stage, the indexes of moisture sensitive include: chilorophyll and MDA contents, SOD activity, the survival time of the plants. Expressed as that, compared to drought sensitive varieties, the chlorophyll contents is higher and more stable, the MDA contents is lower, the SOD activity is stronger, the average survival time is longer than 45 days. In root extending stage, the indexes of moisture sensitive include: leave water contents, MDA and Pro contents,SOD and POD activity. Expressed as that, compared to drought sensitive varieties, the leave water contents is higher than 87.00% and the average amplitude is less than0.75%, the MDA contents is low and Pro contents is higher, the SOD and PODactivity is stronger. In vigorous stage, the indexes of moisture sensitive include:chlorophyll and MDA and Pro contents, SOD and CAT activity. Expressed as that,compared to drought sensitive varieties, the chlorophyll and Pro contents are higher,the MDA contents is lower, the SOD and CAT activity are stronger.It is very compiex of the mechanism of tobacco drought resistance. A good screening method can not only improve the efficiency, but also improve the accuracy of identification. Weighing method can farthest ensure the strength of treatment by weighing. It is more comparable using subordinate function value method to analysis the response to the drought of different variety in the form of quantitation. It is a fast and accurate method to identify tobacco drought resistance by weighting method to control soil moisture content and using subordinate function to evaluate materials,resistance.The drought resistance traits heredity is not the same between different varieties.It shows that the general combining ability of NC82 and NO.3 of Nan-Jiang are more positive values, NC82 and NO. 3 of Nan-Jiang are the strong ability of drought resistance parents by analysising the combining ability of the drought resistance indexes. The special combining ability of K326×NO.3 of Nan-Jiang is high shows that it is a strong ability of drought resistance hybrid.In this study, at seeding stage, NC82 and Hong Hua Da Jin-yuan witch were screened as high drought-resistance varieties and TN90 was screened as drought sensitive varieties. In Huan-breeding stage, K326 was identified as a high drought resistance varieties, TN90 and number 2 of Jiu Cai-ping were identified as drought sensitive varieties. In root extending stage, K326 and number 3 of Nan-Jiang were identified as high drought resistance varieties, NC82 ? TN90 and number 2 of Jiu Cai-ping were identified as drought resistance varieties. In vigorous stage, K326 and NO. 3 of Nan-Jiang were identified as high drought resistance varieties, TN90?Hong Hua Da Jin-yuan?NC82×NO.2 of Jiu Cai-ping and NC82×Hong Hua Da Jin-yuan were identified as drought sensitive varieties. |
PDF Full Text Request